Run by the German performance car magazine, Sport Auto, the Tuner GP started off as an internal test day at Hockenheim 17 years ago. A few readers turned up, and the following year Sport Auto decided to turn it into a full-blown spectator event, with a drift challenge thrown in for good measure.

The rules are simple. Every entrant must be totally road legal, with the TÜV certification to prove it. In Germany, every single part that goes on sale, even a wooden gear knob, has to be tested and certified by the TÜV authorities, to guarantee perfect fit and safety in operation.

Just as with normal organized motorsport, the cachet of winning the Tuner GP means a lot in image and sales terms. Because of this, the interpretation of "road legal" became rather ambiguous over the years.

The great thing about fully adjustable coilovers is that you can make them comfortable enough for road use at one end of the spectrum, and firm enough for track-day use at the other. That said, a track-day setup on a road car is still far off the settings for a true racing car.

However, in 2004, a number of cars came close to being thinly disguised racecars, and were protested by other competitors. The following year, Sport Auto and Dekra, the official third party scrutineers, made doubly sure that the interpretation of "road legal" left nothing to the imagination.

The Tuner GP normally takes place at the end of May, but due to public holidays, it was a month later this year. The format is practice sessions on Friday afternoon and the event proper on Saturday morning, with the Drift Challenge after lunch.

The event was originally divided into half a dozen classes. But as the age of the performance SUV and turbodiesel dawned, more classes were added, and coupes and cabriolets were also split off. There are now separate classes for naturally aspirated and forced induction sedans, while the kerfuffle over the street legal issue spawned the Open Class, where anything goes.

Things tend to get boring and predictable if you have exactly the same program every year, so the organizers try to vary things to keep interest high. However, the suggested third event for this year, a 400-meter sprint, was cancelled, as there were too few entrants.

In past years, a fastest lap was the clincher for a class, or overall win. The major change this year was the averaging of five flying laps, thus putting consistent speed ahead of one blinding lap.

In terms of marques, while BMWs have always figured heavily in the Drift Challenge, the cars have not been represented in the Tuner GP itself since 2006. This is a strange state of affairs as the M3 is a fairly effective track-day tool.

This year, however, BMW made a big comeback with two M3s and a 335i. The E92 M3 entered by A-Work, a Munich-based BMW, MINI and Porsche race and road tuning specialist, entering the Tuner GP for the very first time. With just a sport exhaust on a stock engine, the company's E92 M3 won the Naturally Aspirated Sedan Class in the hands of legendary multiple Tuner GP winner, Wolfgang Kaufmann. His 1 minute, 12.534-second average and 1:12.201 fastest lap put the A-Work M3 right up with some of the slower turbocharged Porsches.

The other M3 was the VF Engineering-supercharged E46 M3 CSL entered by Auto Tauber. Its 1:12.787 average and 1:12.656 fastest lap earned a well-deserved second in the Coupe/Cabriolet Class, sandwiched between TechArt's spectacularly fast GTstreet R Cabriolet and the Vath SLK55 Compressor.

Proving the point that a well set up 335i can actually be faster than an M3, Evotech Motorsport's torquey 397-hp 335i posted a 1 minute, 11.863-second average and a 1:11.681 fastest lap. Running in the Open Class, for cars with modifications that aren't street legal, it finished third after Welzel Motorsport's single-seat formula car and THF Racing's Porsche GT3 RS.

It used to be a foregone conclusion that a Mercedes-AMG car could never achieve a podium finish in the annual GP. A heavy, automatic, rear-driven car, no matter how powerful, simply stood little chance against the hordes of Porsche 911s and BMW M3s.

This was the year that changed all that. Not only did a pair of C63 AMG-based cars from Vath and Lorinser snatch second and third places on the podium, the Vath C63 that came close second in the C3 Class (naturally aspirated sedans) to the very quick M3 was the estate car (wagon) version.

However, when the stopwatches were punched, the Vath T-Model was a mere 0.6 seconds behind, its 1:13.056 average in the hands of Andreas Gulden. This was the fastest time ever set by a Mercedes in the GP's 17 years.

As with all motorsport events, driver skill is a big part of the equation, with the ability to reach peak performance and hold it over the measured laps critical for a class or overall win.On that score, Wolfgang Kaufmann had a slight edge in consistency, even if his and Gulden's best flying laps came a lot closer than their averages. The 430-hp M3's fastest lap was 1 minute, 12.201 seconds, while the 565-hp Vath V63 RS clocked an impressive 1:12.801. Both times are very quick for this class.

Tires are a big factor in the lap time battle, and even on the relatively short 1.63-mile-long Hockenheim Club Circuit, they can make close to three seconds difference to a lap. This was clearly highlighted in the C3 Class, where the M3 and Vath cars ran on the street-legal rubber allowed under the rules, while the Lorinser LV8 was on Continental Sport Contact 3 street tires simply because Conti's new track-day tires will not be available until the autumn. Thus, the 500-hp Lorinser LV8, driven by Sasha Bert, recorded a 1:15.717 average with a 1:15.397 best lap.

Vath was very prolific this year, and Andy Gulden also drove the 575-hp V63 RS in the C12 GT (naturally aspirated) Class where he finished third behind the very quick Cargraphic GT3 RSC 4.0 and the TiKT Performance Corvette. Ironically, this slightly more powerful and lighter sedan was slower than the estate with a 1:14.105 average and 1:13.712 best.

The third Vath car was the SLK55 V58K fitted with a factory Eaton supercharger running on relatively low boost for 450 hp. Entered in the C9 Forced Aspirated Cabriolet Class, it was no match for the TechArt GTstreet R Cabriolet or the Auto Tauber BMW M3, and finished third with a 1:22.760 average and 1:18.299 fastest lap.

Last but not least in the Vath contingent was the very purposeful looking 190E 2.3-16 Evo II that rivaled the winning MTM S1 Quattro rally car in the C16 Youngtimer Class (for bringing back memories of the good old days). This car is actually a 2.3-16 that was brought up to 2.5-16 Evo II bodywork spec. It was of particular interest because of its engine modifications, with the K-Jetronic injection system replaced by a Magneti-Marelli fully-mapped ignition/fuel-injection system using a single throttle per cylinder. A bespoke airbox with conical filter adds to the deep, gurgling induction sound when you pin the throttle to the lightweight carpet, and helps bump peak power to around 270 hp. Inside, a full bolted-in roll cage, race-style deep-dish steering wheel, and lightweight race seats trimmed in leather and Alcantara, endorse the car's track-day intentions. The ironic counterpoint to all this serious race hardware is the early '90s-style car phone cradle on the center console. But even 270 hp, a race-style front splitter and sticky track day Yokohamas only took this venerable homologation special to a third-in-class finish. It clocked a 1 minute, 19.311-second average, with a 1:19.183 best.

The Drift Challenge was more of an exhibition this year than a competition. As usual, MKB's Werner Gusenbauer was inch-perfect all the way in MKB's new 581-hp CLK63 drift car, and received a resounding ovation.

And so to the winners. This year's Tuner GP winner was the TechArt GTstreet RS driven by Jorg Hardt, the 1999 German Formula Ford 1800 Champion and Carrera Cup regular. Anyone watching Hardt drive the 700-hp 911 down to the winning numbers was witnessing an exercise in restraint and consistency behind the wheel. He was line-perfect, and smooth on throttle and steering to the point where the car looked quick but rather unspectacular. The timing clocks said otherwise, however, and his 1 minute, 08.037-second average, with a best lap of 1 minute, 07.709 seconds in a GT2-based Porsche on street legal rubber, was simply awesome. When you consider that this was the same lap time for a 420-hp Le Mans-qualifying Carrera RSR from 1999 with a full race setup and slick tires-from a street legal car-it's mighty impressive.

Because Hockenheim's Club Circuit has very short straights and plenty of challenging corners, it is actually better suited to cars with great handling and grip rather than out-and-out power. If anything, very powerful cars struggle here because they cannot deploy their grunt effectively exiting the tight bends. So while it may seem strange that a 700-hp turbocharged Porsche can only achieve the same lap time as a 420-hp naturally aspirated one, the fact is that a very powerful street car, whether rear- or four-wheel drive, can be a real handful here.

The antithesis of the sleek GTstreet RS, the TechArt Magnum, is brutality personified, both in the way it looks and in the way it eats tarmac. While TechArt offers up to 680 hp with a tweaked twin-turbo V8, this Magnum had a stock Cayenne Turbo S motor because TechArt has not yet homologated the upgraded engine.

Enco is TechArt's traditional rival in the GP's SUV Class, and always puts up a good fight. In this clash of titans, Jorg Hardt drove the Magnum to a 1 minute, 16.939-second average and 1 minute, 16.455-second best lap to take the class win. The even more brutal-looking Enco Cayenne posted a 1 minute, 17.816-second average, piloted by Matthias Kahle. His best lap was 1:17.662.

TechArt's third victory was in the Coupe/Cabriolet Class, where Jorg Hardt took the class win with the white GTstreet R Cabriolet. His 1:09.601 average and 1:09.351 fastest lap showed off not just TechArt's tuning prowess, but also just how good a platform the basic Porsche 997 Turbo Cabriolet is.

Cargraphic was the overall runner-up again, its Turbo RSC GT 3.6 sliding into second place in the Turbo GT Class with a creditable 1:08.641 average and 1:08.417 best lap in the hands of Dominik Schwager.Cargraphic did pull off a win in the Naturally aspirated GT Class with its GT3 RSC 4.0, Timo Kluck driving to a blinding 1:09.748 average and a 1:09.641 fastest lap.

In Europe, Audi is a major contender these days, posting much better sales figures than BMW and Mercedes in these hard times. And with its latest engine and chassis improvements, it is also a force to be reckoned with on the track. MTM entered cars in several classes and came away with a few trophies for the effort. Its formidable 700-hp RS6 R was runner up in the Sedan (Turbo Class), narrowly beaten by the lighter and nimbler Mitsubishi Evo of Import Racing.

However, MTM's mechanic and pro-race driver, Florian Gruber, took the Diesel (over 2.0 liter) Class win with an Audi A5 3.0 TDI, as well as the Funcar (Turbo) Class win with the 318-hp KTM X-Bow. In fact, Gruber's average of 1 minute, 8.536 seconds, and best of 1:07.836, brought him so agonisingly close to the TechArt GTstreet RS for overall fastest time of the day, it hurt.

That, however, is the nature of motorsport and the Sport Auto Tuner Grand Prix.

TechArt Trio -The Right Stuff
Underlining the 2008 victory, TechArt pulled off a real hat trick at this year's Tuner Grand Prix by not only winning the event overall, but also nailing three class wins as well.

A couple of weeks later, I'm at the Mercedes-owned Malmsheim test track near Stuttgart with the three TechArt machines glowing in the late afternoon sun, raring to go. Even stripped of their Tuner GP race numbers and stickers, they still look purposeful, and in the case of the black GTstreet RS, brutal.

I've driven all these cars before, but it is fitting that after their big win I should re-acquaint myself with the qualities that help them stand head and shoulders over the competition.

I climb into the chunky Magnum first. This particular Magnum is based on the latest-spec Cayenne Turbo S, but a normal Turbo is also a good starting point. TechArt has sold nearly 900 of these beasts since the Magnum concept was rolled out back in 2003. Bearing in mind that a fully decked-out Magnum doubles the price of the Cayenne Turbo, this is no mean achievement.

The TechArt Magnum's Class win was made sweeter by the fact that its 550-hp engine is stock apart from the free-flow sport exhaust that provides a truly lovely V8 bellow when you accelerate. Other than Magnum body styling, 30mm lower ride height and 23-inch wheels, this rest of the car also remains mechanically factory spec.The chassis upgrade makes the big five-door Porsche turn in and grip even more impressively than usual, and gives you the confidence to deploy its 550 horses with more gusto. Direction changes are crisper, and mechanical grip is in another league.

As the evening sky moves towards a gorgeous sunset, the white GTstreet R Cabriolet beckons. Using a Turbo Cabriolet as its starting point, it has been endowed with 660 hp and blasts to 62 mph in just 3.4 seconds, and on to 214 mph. The aerodynamic additions add 10kg of downforce over both axles at speed, while the big 8.5 and 12.0x20-inch forged alloy wheels and 245/30 and 315/25 tires make the most of the traction delivered by the all-wheel-drive system.

While many Cabriolet owners like the Tiptronic transmission for easy cruising, this car has a manual six-speed, and is all the more hardcore for it. Rocketing off the line, the boosted motor revs faster than stock and you have to pay attention to avoid hitting the rev limiter in the first two ratios. The half-mile-long runway is eaten up in seconds, and I have to really lean on the PCCB ceramic brakes as the end approaches. Loading the car up under power in a sweeping turn to go back the way I came shows just how stable and flex-free the 997 Cabriolet shell is.

On to the Champion. I first speed-tested the GT2-based TechArt GTstreet RS at Malmsheim in September 2008. This 700-hp machine does exactly what it says on the tin, with a devastating mix of blinding straight line go, precise handling and awesome grip.

"Street" is its middle name however, and none of this would be relevant if it wasn't civilized enough to also be a daily driver. TechArt's fully adjustable coilover suspension allows you to dial it up for the track and then back down again when you drive home.

Importantly, the optional hydraulic Noselift system raises the front of the car by a generous 60mm to clear car park ramps and speed bumps. Both major manufacturers and tuners have always successfully exploited the link between road and racecars. "Win on Sunday, sell on Monday" is one of the most effective sales philosophies ever conceived, and since its Tuner GP victory, TechArt's phones have been ringing off the hook. -IK